The connection of two or more wires is called a “splice,” and an “open splice” is when it is not contained inside a box. When electrical wire connections come apart, the sparking and heat from the electricity jumping between loosened wires can easily light any adjacent flammable material on fire. Also, unprotected wire connections can be a shock hazard. So the number-one basic safety requirement of the electrical code is that wire connections should be secured in a fire-resistant box. The box can be as big as the main electric panel or small as a receptacle box in the wall. 

   The specific requirements of an electrical splice are:

1. The splice must be made in a junction box or enclosure rated for the use.
2. The splice must be made with approved electrical connectors (typically wire nuts) that are rated for the wire size and number of wires connected.
3. The cable or wires should be secured where they enter the box, so that the splice cannot be pulled apart by tugging the cable from outside the box.
4. The box must have a cover.
5. It should be installed at an accessible location.

   In the photo above, they didn’t even bother to use wire nuts. A more typical example would be wire splices in an open electrical box, often overstuffed, as below.

These requirements do not apply to low-voltage wiring, such as the wires running from a thermostat to an air conditioning system.

    Also, see our blog post Does a wire nut connection need to be wrapped with electrical tape?

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Here’s links to a collection of our other blog posts about ELECTRICAL WIRING:

• Which house appliances need a dedicated electrical circuit?

• Can a short circuit cause a high electric bill?

• How can I find out the size of the electric service to a house?

• Can old electrical wiring go bad inside a wall? 

• What are the most common electrical defects found in a home inspection? 

• What is the life expectancy of electrical wiring in a house? 

• What is an "open junction box"? 

• How dangerous is old electrical wiring? 

• What is a ground wire? 

• I heard that aluminum wiring is bad. How do you check for aluminum wiring?  

• What is "knob and tube" wiring?  

• What is the code requirement for receptacle outlets in a closet?

   Visit our ELECTRICAL page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.